1. Field of the Invention
The present application relates to a composition in the form of an oil-in-water emulsion comprising at least one acrylic terpolymer and to the use of the composition, in particular for caring for and/or treating the skin of the body or of the face, the hair and/or the lips and especially for caring for dry skin and/or dry lips.
2. Discussion of the Background
For various reasons relating in particular to better comfort of use (softness, emollience and others), current cosmetic compositions are generally provided in the form of an emulsion of the oil-in-water (O/W) type composed of a continuous aqueous dispersing phase and of a non-continuous oily dispersed phase or of an emulsion of the water-in-oil (W/O) type composed of a continuous oily dispersing phase and of a non-continuous aqueous dispersed phase. O/W emulsions are the most in demand in the cosmetics field because they comprise an aqueous phase as external phase, where the aqueous phase confers, during application to the skin, a fresher, less greasy and lighter feel than W/O emulsions.
The emulsions are generally stabilized by appropriate emulsifying surfactants which, by virtue of their amphiphilic structure, become positioned at the oil/water interface and thus stabilize the dispersed droplets. These emulsifiers exhibit the disadvantage, however, of being penetrating and potentially irritating to the skin, eyes and scalp, in particular for subjects with sensitive skin.
In addition, such emulsions can have inadequate cosmetic and physicochemical properties (oily feel, instability over time). Increasing the level of surfactants does not generally solve these problems. The required stability is not always achieved and the cosmetic properties are not improved (waxy and heavy feel and lack of freshness on application). Furthermore, as indicated above, it is also inadvisable to use an excessively high level of surfactant so as to ensure harmlessness.
One solution for achieving freedom from the phenomena of instability of the O/W emulsions (creaming and phase separation) consists in adding thickening agents to the emulsion. The function of which thickening agents is to create, within the aqueous phase, a gelled matrix which serves to set the oily droplets and which provides for mechanical maintenance of the entire emulsion. However, this solution exhibits the disadvantage of not making it possible to obtain all the desired textures and in particular fluid and light textures which are readily and rapidly applied to the skin without leaving a residual film.
Furthermore, the replacement of the surfactants by polymers comprising, in their chains, a hydrophilic part and a hydrophobic part composed of a fatty chain, such as copolymers of (C.sub.10 -C.sub.30)alkyl acrylate and of acrylic or methacrylic acid, for example the product "Pemulen TR2" sold by Goodrich, has been envisaged. However, these polymers exhibit the disadvantage of not making it possible to obtain a composition which remains stable for a long period of time when the amount of oil is too high or when the emulsion is very fluid, that is to say in the case where the aim is to minimize the level of polymer in order not to have a thick emulsion.